<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Db
 * @subpackage Adapter
 * @copyright  Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: Pgsql.php 23775 2011-03-01 17:25:24Z ralph $
 */

/**
 * @see Zend_Db_Adapter_Pdo_Abstract
 */
require_once 'Zend/Db/Adapter/Pdo/Abstract.php';

/**
 * Class for connecting to PostgreSQL databases and performing common operations.
 *
 * @category   Zend
 * @package    Zend_Db
 * @subpackage Adapter
 * @copyright  Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Db_Adapter_Pdo_Pgsql extends Zend_Db_Adapter_Pdo_Abstract {
	
	/**
	 * PDO type.
	 *
	 * @var string
	 */
	protected $_pdoType = 'pgsql';
	
	/**
	 * Keys are UPPERCASE SQL datatypes or the constants
	 * Zend_Db::INT_TYPE, Zend_Db::BIGINT_TYPE, or Zend_Db::FLOAT_TYPE.
	 *
	 * Values are:
	 * 0 = 32-bit integer
	 * 1 = 64-bit integer
	 * 2 = float or decimal
	 *
	 * @var array Associative array of datatypes to values 0, 1, or 2.
	 */
	protected $_numericDataTypes = array (Zend_Db::INT_TYPE => Zend_Db::INT_TYPE, Zend_Db::BIGINT_TYPE => Zend_Db::BIGINT_TYPE, Zend_Db::FLOAT_TYPE => Zend_Db::FLOAT_TYPE, 'INTEGER' => Zend_Db::INT_TYPE, 'SERIAL' => Zend_Db::INT_TYPE, 'SMALLINT' => Zend_Db::INT_TYPE, 'BIGINT' => Zend_Db::BIGINT_TYPE, 'BIGSERIAL' => Zend_Db::BIGINT_TYPE, 'DECIMAL' => Zend_Db::FLOAT_TYPE, 'DOUBLE PRECISION' => Zend_Db::FLOAT_TYPE, 'NUMERIC' => Zend_Db::FLOAT_TYPE, 'REAL' => Zend_Db::FLOAT_TYPE );
	
	/**
	 * Creates a PDO object and connects to the database.
	 *
	 * @return void
	 * @throws Zend_Db_Adapter_Exception
	 */
	protected function _connect() {
		if ($this->_connection) {
			return;
		}
		
		parent::_connect ();
		
		if (! empty ( $this->_config ['charset'] )) {
			$sql = "SET NAMES '" . $this->_config ['charset'] . "'";
			$this->_connection->exec ( $sql );
		}
	}
	
	/**
	 * Returns a list of the tables in the database.
	 *
	 * @return array
	 */
	public function listTables() {
		// @todo use a better query with joins instead of subqueries
		$sql = "SELECT c.relname AS table_name " . "FROM pg_class c, pg_user u " . "WHERE c.relowner = u.usesysid AND c.relkind = 'r' " . "AND NOT EXISTS (SELECT 1 FROM pg_views WHERE viewname = c.relname) " . "AND c.relname !~ '^(pg_|sql_)' " . "UNION " . "SELECT c.relname AS table_name " . "FROM pg_class c " . "WHERE c.relkind = 'r' " . "AND NOT EXISTS (SELECT 1 FROM pg_views WHERE viewname = c.relname) " . "AND NOT EXISTS (SELECT 1 FROM pg_user WHERE usesysid = c.relowner) " . "AND c.relname !~ '^pg_'";
		
		return $this->fetchCol ( $sql );
	}
	
	/**
	 * Returns the column descriptions for a table.
	 *
	 * The return value is an associative array keyed by the column name,
	 * as returned by the RDBMS.
	 *
	 * The value of each array element is an associative array
	 * with the following keys:
	 *
	 * SCHEMA_NAME      => string; name of database or schema
	 * TABLE_NAME       => string;
	 * COLUMN_NAME      => string; column name
	 * COLUMN_POSITION  => number; ordinal position of column in table
	 * DATA_TYPE        => string; SQL datatype name of column
	 * DEFAULT          => string; default expression of column, null if none
	 * NULLABLE         => boolean; true if column can have nulls
	 * LENGTH           => number; length of CHAR/VARCHAR
	 * SCALE            => number; scale of NUMERIC/DECIMAL
	 * PRECISION        => number; precision of NUMERIC/DECIMAL
	 * UNSIGNED         => boolean; unsigned property of an integer type
	 * PRIMARY          => boolean; true if column is part of the primary key
	 * PRIMARY_POSITION => integer; position of column in primary key
	 * IDENTITY         => integer; true if column is auto-generated with unique values
	 *
	 * @todo Discover integer unsigned property.
	 *
	 * @param  string $tableName
	 * @param  string $schemaName OPTIONAL
	 * @return array
	 */
	public function describeTable($tableName, $schemaName = null) {
		$sql = "SELECT
                a.attnum,
                n.nspname,
                c.relname,
                a.attname AS colname,
                t.typname AS type,
                a.atttypmod,
                FORMAT_TYPE(a.atttypid, a.atttypmod) AS complete_type,
                d.adsrc AS default_value,
                a.attnotnull AS notnull,
                a.attlen AS length,
                co.contype,
                ARRAY_TO_STRING(co.conkey, ',') AS conkey
            FROM pg_attribute AS a
                JOIN pg_class AS c ON a.attrelid = c.oid
                JOIN pg_namespace AS n ON c.relnamespace = n.oid
                JOIN pg_type AS t ON a.atttypid = t.oid
                LEFT OUTER JOIN pg_constraint AS co ON (co.conrelid = c.oid
                    AND a.attnum = ANY(co.conkey) AND co.contype = 'p')
                LEFT OUTER JOIN pg_attrdef AS d ON d.adrelid = c.oid AND d.adnum = a.attnum
            WHERE a.attnum > 0 AND c.relname = " . $this->quote ( $tableName );
		if ($schemaName) {
			$sql .= " AND n.nspname = " . $this->quote ( $schemaName );
		}
		$sql .= ' ORDER BY a.attnum';
		
		$stmt = $this->query ( $sql );
		
		// Use FETCH_NUM so we are not dependent on the CASE attribute of the PDO connection
		$result = $stmt->fetchAll ( Zend_Db::FETCH_NUM );
		
		$attnum = 0;
		$nspname = 1;
		$relname = 2;
		$colname = 3;
		$type = 4;
		$atttypemod = 5;
		$complete_type = 6;
		$default_value = 7;
		$notnull = 8;
		$length = 9;
		$contype = 10;
		$conkey = 11;
		
		$desc = array ();
		foreach ( $result as $key => $row ) {
			$defaultValue = $row [$default_value];
			if ($row [$type] == 'varchar' || $row [$type] == 'bpchar') {
				if (preg_match ( '/character(?: varying)?(?:\((\d+)\))?/', $row [$complete_type], $matches )) {
					if (isset ( $matches [1] )) {
						$row [$length] = $matches [1];
					} else {
						$row [$length] = null; // unlimited
					}
				}
				if (preg_match ( "/^'(.*?)'::(?:character varying|bpchar)$/", $defaultValue, $matches )) {
					$defaultValue = $matches [1];
				}
			}
			list ( $primary, $primaryPosition, $identity ) = array (false, null, false );
			if ($row [$contype] == 'p') {
				$primary = true;
				$primaryPosition = array_search ( $row [$attnum], explode ( ',', $row [$conkey] ) ) + 1;
				$identity = ( bool ) (preg_match ( '/^nextval/', $row [$default_value] ));
			}
			$desc [$this->foldCase ( $row [$colname] )] = array ('SCHEMA_NAME' => $this->foldCase ( $row [$nspname] ), 'TABLE_NAME' => $this->foldCase ( $row [$relname] ), 'COLUMN_NAME' => $this->foldCase ( $row [$colname] ), 'COLUMN_POSITION' => $row [$attnum], 'DATA_TYPE' => $row [$type], 'DEFAULT' => $defaultValue, 'NULLABLE' => ( bool ) ($row [$notnull] != 't'), 'LENGTH' => $row [$length], 'SCALE' => null, // @todo
'PRECISION' => null, // @todo
'UNSIGNED' => null, // @todo
'PRIMARY' => $primary, 'PRIMARY_POSITION' => $primaryPosition, 'IDENTITY' => $identity );
		}
		return $desc;
	}
	
	/**
	 * Adds an adapter-specific LIMIT clause to the SELECT statement.
	 *
	 * @param string $sql
	 * @param integer $count
	 * @param integer $offset OPTIONAL
	 * @return string
	 */
	public function limit($sql, $count, $offset = 0) {
		$count = intval ( $count );
		if ($count <= 0) {
			/**
			 * @see Zend_Db_Adapter_Exception
			 */
			require_once 'Zend/Db/Adapter/Exception.php';
			throw new Zend_Db_Adapter_Exception ( "LIMIT argument count=$count is not valid" );
		}
		
		$offset = intval ( $offset );
		if ($offset < 0) {
			/**
			 * @see Zend_Db_Adapter_Exception
			 */
			require_once 'Zend/Db/Adapter/Exception.php';
			throw new Zend_Db_Adapter_Exception ( "LIMIT argument offset=$offset is not valid" );
		}
		
		$sql .= " LIMIT $count";
		if ($offset > 0) {
			$sql .= " OFFSET $offset";
		}
		
		return $sql;
	}
	
	/**
	 * Return the most recent value from the specified sequence in the database.
	 * This is supported only on RDBMS brands that support sequences
	 * (e.g. Oracle, PostgreSQL, DB2).  Other RDBMS brands return null.
	 *
	 * @param string $sequenceName
	 * @return string
	 */
	public function lastSequenceId($sequenceName) {
		$this->_connect ();
		$sequenceName = str_replace ( $this->getQuoteIdentifierSymbol (), '', ( string ) $sequenceName );
		$value = $this->fetchOne ( "SELECT CURRVAL(" . $this->quote ( $this->quoteIdentifier ( $sequenceName, true ) ) . ")" );
		return $value;
	}
	
	/**
	 * Generate a new value from the specified sequence in the database, and return it.
	 * This is supported only on RDBMS brands that support sequences
	 * (e.g. Oracle, PostgreSQL, DB2).  Other RDBMS brands return null.
	 *
	 * @param string $sequenceName
	 * @return string
	 */
	public function nextSequenceId($sequenceName) {
		$this->_connect ();
		$sequenceName = str_replace ( $this->getQuoteIdentifierSymbol (), '', ( string ) $sequenceName );
		$value = $this->fetchOne ( "SELECT NEXTVAL(" . $this->quote ( $this->quoteIdentifier ( $sequenceName, true ) ) . ")" );
		return $value;
	}
	
	/**
	 * Gets the last ID generated automatically by an IDENTITY/AUTOINCREMENT column.
	 *
	 * As a convention, on RDBMS brands that support sequences
	 * (e.g. Oracle, PostgreSQL, DB2), this method forms the name of a sequence
	 * from the arguments and returns the last id generated by that sequence.
	 * On RDBMS brands that support IDENTITY/AUTOINCREMENT columns, this method
	 * returns the last value generated for such a column, and the table name
	 * argument is disregarded.
	 *
	 * @param string $tableName   OPTIONAL Name of table.
	 * @param string $primaryKey  OPTIONAL Name of primary key column.
	 * @return string
	 */
	public function lastInsertId($tableName = null, $primaryKey = null) {
		if ($tableName !== null) {
			$sequenceName = $tableName;
			if ($primaryKey) {
				$sequenceName .= "_$primaryKey";
			}
			$sequenceName .= '_seq';
			return $this->lastSequenceId ( $sequenceName );
		}
		return $this->_connection->lastInsertId ( $tableName );
	}

}
